Power supply system



Jan 14, 194-1. H. BRIEBRECHER 2,228,868

POWER SUPPLY SYSTEM File d Oct. 21, 1958 INVENTOR HAROLD 52/ sear/1m ATTORNEY UNITE STATES PATENT POWER SUPPLY SYSTEM Harold Briebrecher, Eerlin-Reiniokendorf, Germany, assignor to General Electric Company, a corporation of New York Application October 21, 1938, Serial No. 236,139 In Germany October 30, 1937 3 Claims. ((31. 179-171) This invention is concerned With a circuit orthe usual way by the cathode resistance R2 so ani t On adapt d to ampli y ieeble electric pothat, as before outlined, there occur appreciable tentials, especially the voltage variations caused changes in the plate current as a result of supby photo-electric cells in measuring amplifiers in ply line voltage fluctuations.

which the plate current of the amplifier tube is Figs. 2 and 3 illustrate two exemplified em- 5 to be kept independent of and unaiiected by the bodiments of the circuit arrangement as here fluctuations of the supply-line voltage. disclosed.

If conventional amplifiers are connected with The fall of potential occasioned at the filament the supply line, there results a marked dependor heater of the tube serves for biasing the grid.

once of the amplified current upon the fluctua- Owing to the temperature dependence of the 10 tions of the line potential, and this occasions an heater, for instance, in the presence of the line uncontrollable variation of the plate current. potential of +10 percent, there results a change This dependence is particularly pronounced when in the negative grid potential being twice as the amplifier is associated with a D. 0. supply large, say, for instance, percent, whence there 15 line. is a chance to compensate by the aid of such 15 An amplifier arrangement of his kind known grid voltage Variations the eiiects of the plate in the prior art is illustrated in Fig. l. The heatand the heating voltage variations. As a reing current of the indirectly heated tube 1 is set sult the plate current becomes largely independto the proper value by the agency of the series ent of the fluctuations of the supply line voltresistance R1. The grid and the plate potentials age. 29 as well as the voltage for the photo-electric cell By the arrangement here disclosed it becomes are derived from the voltage divider comprising readily feasible to make the shape of the grid the resistances R2 and R3. Thus, if the supplypotential charcateristic as a function of the supline potential varies, say +19 percent, then the ply line voltage variations as may be desired L5 potential U2 of the plate and the potential U1 in dependence uponthe grid transparency, the

of the grid will vary in the same proportion. drive range, etc. The case also may arise Where The fall of voltage at the filament oi the tube, the fluctuations of the supp y- Voltage y Sihowever, because of the temperature dependence multaneous automatic grid voltage variations of the filament resistance, grows roughly in may thus be over-compen a in o r Words,

double proportion, that is, by around 20 perthat the plate current, upon an increase in the cent. This growth of the plate potential and the line potential, will not onl rise, but even difilament potential results in a rise of plate curminish.

rent. The simultaneous rise of the negative grid According to a further object of the invention bias voltage U1, to be sure, partly counteracts the g d b asi Vol age of tube l is not taken 5 such an increment, but it is discovered that in n y from. or cro s. resistance R4, t rather this arrangement, with the majority of types of from a series arrangement Compris g the heattube, there results a change in the plate current or resistance R4 and a fixed resistance R5. Acamounting to twice or even three times the ording by suitame (3 0f the fi e change in the supply line voltage so that this resistance R5 in relation to the resistance R4 of amplifier scheme becomes unserviceable for prethe filament it is possible to secure the desired cise measurements. grid bias voltage for any desired tube. The

Now, by the object of the present invention compens y effefit y d Voltage V ti is these drawbacks are obviated by using the fall ost ma ed or 565 0. It becom s so much of voltage occasioned at the filament of the tube lower, the less R5 comp 0 4- to act as the grid biasing voltage with the conse- This arrangement not only offers a chance to 40 quencc that the plate current of the amplifier stabilize the plate current at a value independent tube becomes perfectlyunafiected by fluctuations of the fluctuations of the supply line voltage, but of line potential. it is, for instance, also possible to cause the plate For a more detailed explanation of the object current, with growth of the line voltage, to either of this invention reference is made to the apraise or decline at a certain rate and proportion.

pended drawing. I claim:

In Fig. 1 is shown. a discharge tube I together 1. In an electrical circuit, an electronic tube with a photo-electric cell 2 connected in an amhaving an anode, an indirectly heated cathode, a plifier circuit organization in which the proheater filament for the cathode, and a grid elecduction of the grid biasing voltage is effected in trode, said heater filament having a resistance 55 which increases with increasing current through it, a network across which is available a line voltage, the value of the line voltage being subject to variations, means for applying a voltage derived from said line voltage between the anode and cathode of said tube, a circuit for energizing the heater filament comprising a constant resistance and said filament in series connected across said network, said circuit being arranged to cause an increase in the line voltage to produce a proportionately larger increase in the drop across the filament and means for impressing between the grid electrode and the cathode a voltage which is dependent upon the voltage drop across the filament.

2. In an electrical circuit, an electronic tube having an anode, an indirectly heated cathode, a heater filament for the cathode, and a grid electrode, said heater filament being characterized by that its resistance increases with increasing current through it, a network across which is available a voltage the value of which is liable to vary, means for applying a voltage derived from said network between the anode and cathode of the tube, means including a seriesconstant resistance device for connecting the filament across said network, said constant resistance device being arranged to cause the filament voltage to increase in greater proportion than increases occurring in the network voltage, and means for impressing the voltage drop developed across the filament, between the grid electrode and the cathode.

3. In signalling apparatus including at least one electronic tube having an indirectly heated cathode, an anode and a grid electrode, a pair of terminals adapted to be connected to a source of potential, a source of input voltage, a load, a filament for heating the cathode, means imeluding a series impedance for connecting the filament across said two terminals, means including said impedance for connecting the oath- 

